Control system for a concrete block forming machine



April 21, 1964 CONTROL SYSTEM FOR A CONCRETE BLOCK FORMING MACHINE Filed May 9, 1962 2 Sheets-Sheet 1 INVENTOR. HARRY A. WELLNQTZ MAHONEY ,MILLER 8| RAMBO ATTO RN EYS H. A. wELLNl-rz 3,129,482 x 2 sneeis-sneet 2 MAHONEY, MILLER 8 RAMBO.

ATTORNEYS April 21. 1964 H. A. wELLNlTz CONTROL lSYSTEM FOR A CONCRETE BLOCK FORMING MACHINE Filed May 9, 1962 Z RW ON, O O TL 4 3 WL l. VE EO 2 RO B c NT /\.|T A mw Vm Y R R A H m Rm n IDT 7 9 O 4 74 Y 8 l`ML 7 6 w m 7 n. O 7 8v United States Patent O 3,129,482 CONTROL SYSTEM FR A CONCRETE BLCK FRMING MACHINE Harry A. Wellnitz, 231 N. Princeton Ave., Columbns 22, @his Filed May 9, 1962, Ser. No. 193,565 2 Claims. (Ci. ZS-) This invention relates to a control system for a concrete block forming machine. It has to do, more particularly, with a control arrangement which is applicable to a type of concrete block machine now commonly in use for insuring that the blocks formed thereon are of accurate predetermined height without regard to the thickness of the pallets upon which the blocks are formed.

One type of concrete block forming machine now commonly in use includes a sliding material feed box movable between a material-receiving position and a material-discharge position over a mold box open at its top and bottom edges. By a suitable pallet conveyor arrangement, mold pallets are moved successively into association with the mold box at its lower edge. As it is moved into association with the mold box, each pallet is supported by a frame and is raised thereby into contact with the lower edge of the mold box and remains there during the molding operation. Part of this molding operation occurs after the feed box is moved away from the mold box and at which time a stripper head is moved downwardly by its supporting frame into association with the upper edge of the mold box and will rest freely on the material therein. The mold box is provided with means for vibrating it during the molding operation. This vibration causes the block material to settle in the mold box on the pallet with the pressure stripper head freely following and contacting the settling material so as to etlectively compact it. The pressure stripper head is positively moved downwardly relative to the mold box to strip the block from the mold box shortly after the vibration of the mold box is interrupted. At the same time, by a suitable positive mechanical connection between the pressure stripper head frame and the pallet frame, the pallet support frame is also moved downwardly so that the pallet moves downwardly simultaneously with the pressure stripper head, the formed block being held between the pallet and the head during this downward movement. This positive mechanical connection comprises fixed depending push rods on the pressure stripper head frame which will gradually move into engagement with fixed upstanding pushV rods on the pallet frame as the pressure stripper head frame settles downwardly during the mold vibration. When the push rods on the pressure stripper head frame contact the push rodsY on the pallet support frame, an electric control circuit is actuated which stops the vibrating means, and actuates an electric drive motor to drive a series of cams which force the pressure stripper head frame and the pallet support frame downwardly together and starts other operations of the machine.

An attempt was made in connection with this machine to accurately control the height of the formed block by having the push rods form the electrical contacts for the electric circuit which, when engaged, stop the vibration and start the stripping operation. However, since one of these contacts was carried by the pallet support frame, the thickness of the pallet had an influence on the instant of contact. Consequently, the thicknms of the pallet affected the height of the formed block, variations in thicknesses of successive pallets producing variations in height of the successively formed blocks. Y

According to the invention disclosed in my Patent No. 2,985,935, issued May 30, 1961, the control circuit was so arranged that the thickness of the pallet would have no eiect on the height of the formed block. The push rods on the pressure stripper head frame and the pallet support frame were not relied upon to complete the circuit to stop the vibration and start the stripping action but the circuit control contacts were provided on the pressure stripper head frame and the mold box so that they would gradually come into contact during the vibrating operation. Thus, the block height measurement was taken off the mold box rather than olf the pallet support frame. However, to insure proper positive rigid connection between the pressure stripper head frame and the pallet support frame during the stripping action, there Was also provided, according to that patent, electrically actuated means for bringing the adjacent ends of the push rods into irm mechanical contact at the instant of engagement of the circuit control contacts, regardless of the exact relative vertical positions of the two frames at that time. This insured that there wouldy be no sudden compressive action on the formed green block, thereby avoiding fracture, but the block would be firmly held between the pressure stripper head and the pallet which would be moved downwardly simultaneously at the same s eed.

pThe control system of this present invention, like that disclosed in said patent, will be readily adaptable to aV standard machine of the type discussed above with only minor changes in such machine. However, the present invention provides a novel structure for bringing the adjacent ends of the push rods into iirm mechanical contact when desired. This means takes the form of a fluidactuated cylinder and piston unit which is coaxially aligned with one of the push rods which is slidably mounted relative to the other push rod. This cylinder and piston unit, when actuated by the circuit control contacts, will bring the push rods into firm mechanical contact and hold them in contact.

In the accompanying drawings, there is illustrated diagrammatically a blockforming machine of the .general type disclosed in my prior patent with the control system of this present inventionapplied thereto.

In these drawings:

FIGURE 1 is a front elevational view ofY the block-` forming machine with the control system of this inven-` tion applied thereto showing certain parts of the machineV in the ,relative positions they occupy during the blockforming operation.

FIGURE 2 is a similar view but showing the relative positions of the parts of the machine during the stripping operation.

FIGURE 3 is a vertical sectional view taken along line 3 3 of FIGURE 1 showing the electrically controlled fluid-actuated cylinder and piston unit for establishing a rigid connection between the push rods carried by the pressure stripper head frame and pallet support frame.

FIGURE lis a vertical sectional View taken-along line 4 4 of FIGURE 2 showing the block height control electrical contacts carried on the stripper ,frame` and the mold box.

FIGURE 5 is an enlarged detail of the contact of the structure of FIGURE 4.

FIGURE 6 is a schematic circuit diagram of a suitable control circuit for the machine.

FIGURE 7 is a schematic illustration in vertical -section of the cam means controlled by the circuit associated with the units which they control.

FIGURE 8 is aplan View of the cam means of FIG- URE 7.

`spring-loaded With particular reference to the drawings, there is' crete block forming machine which is generally of standard form and which includes mold-box supporting arms 11, a pallet support frame 12, and a pressure stripper head supporting frame 13. A mold box 14 normally rests on the arms 11 which are fixed in a vertical position. The mold box loosely rests on the fixed supporting arms so it can be lifted slightly therefrom during vibration. The mold box 14 is open at its upper and lower sides. The pallet support frame 12 carries the upstanding laterally spaced pallet supports 15 which at their upper ends receive and support a pallet 16 directly below the open bottom of the mold box 14. The pallet support frame 12 is mounted for vertical movement on suitable guides indicated as the fixed guide posts 17. The pressure stripper head frame 13 is provided with the stripper head 18 which includes the depending plungers 19, the lower ends of which will engage the block forming material during the molding `operation and the formed blocks during the stripping operation. The pressure stripper head frame 13 is also mounted for vertical movement on a suitable guide structure which may be the same xed guide posts 17 that carry the pallet frame 12, as shown. Thus, the pallet support frame 12 is movable vertically relative to the mold box 14, the pressure stripper head 'frame 1-3 is movable vertically relative to the mold box 1-4- `and the two frames lare also movable vertical-ly relative to each other.

The mold box 14 may be vibrated by any suitable means and for this purpose the mold box supporting arms 11 carry at each side of the machine ian electric vibrating motor 2li. These motors 20 drive through flexible belts 20a, suitable vibrating means carried by the mold box 14;, indicated generally at 14a and which may be in the form of shafts carrying eccentric weights. As will appear later, at the time of vibrating the mold box 14, it is lifted slightly from the arms 11.

A suitable conveyor system is provided for successively bringing the empty pallets into association with the pallet support frame 12 preparatory to the molding operation and for removing the block carrying pallets therefrom after the molding operation. This conveyor system is not shown in detail but includes the pallet engaging arms 21 (FIGURES 1 and 7) which will move in vertical planes in rectilinear paths, portions of which will be between the pallet supports 15, to move the empty pallet 16 rearwardly over and deposit it on the pallet supports 15, when the pallet support frame 12 is lowered, and for lifting the block-carrying pallet from the supports 15 and withdrawing it forwardly of the support frame 12 after the molding operation.

The machine also includes the feed box 25 which is mounted for forward and rearward movement on the frame 11. The box 25' is movable from a rearward position, shown in FIGURE 7, where it will receive a charge of block-forming material from a feed hopper (not shown) to a forward position in registry with the mold box 14. At this time, the frame 13 and the pressure lstripper head 1S carried thereby will be in a raised position so as not to interfere with the reciprocating movement of the feed box.

The feed box 25 may be reciprocated by suitable linkage 26 actuated by a cam 27 keyed to a driven shaft 28 (FIGURES 7 and 8). The pallet support frame 12 is lifted on the guides 17 by means of suitable linkage 29 actuated by a cam 30 keyed on the shaft `28. This linkage includes a compression spring unit 31 to insure that the pallet is held firmly up against the lower edge of the mold box 14, being compressed slightly upon contact of the pallet 16 with the mold box. The pressure stripper head `frame 13 is moved downwardly, the pallet support frame 12 moving therewith as will later appear, by means of linkage including a lever 32 keyed on a supporting shaft 33. This lever 32 is rocked about the axis of the shaft 33 by a cam 34 lkeyed on the shaft 2S. 'I'he lever 32 is also rocked about the axis `of the shaft 33 by 4 a crank arm 35 which is rocked by a cam 36, keyed on the shaft 28, to raise the pressure stripper head frame 13 without raising the pallet support frame 12. The driven shaft 28 is driven by an electric drive motor 40.

The pallet support frame 12 is provided at each side thereof with an upstanding push rod 41 (FIGURES l and 2) rigidly mounted thereon. The pressure stripper head frame 13 is provided with aligning depending push rods 42 but, according to this invention, these rods are not rigidly attached to the frame 13 but are mounted for limited vertical movement relative to the frame.

The mounting for each of these rods 42 is shown in FIGURES l, 2 and 3 as comprising a rectangular open bracket -4'3 which is rigidly secured to and depends from the pressure stripper head frame 13. A bushing 44 is threaded into the lower side Iof the bracket 43 and the rod 42 is splined for free vertical sliding but non-rotative movement therein. A stop 45 limits upward movement of the rod 42 relative to the bushing to a position wherel its upper end is substantially flush with the upper end of the bushing. A tension spring 46 is connected to the rod 42 and to the lower part lof the bracket 43 and normally holds the rod 42 upwardly to cause the stop 45 to engage the lower end of bushing 44. Also, the spring prevents dropping of the -rod from the bushing. Thus, the rcd 42 is normally suspended from the bracket 43J Within the bracket 43 there is positioned a fluid-actuated unit or ram which is shown as being a cylinder and piston unit 48. Il'his unit comprises a cylinder 49 which is provided with a vertically movable piston 50a having a downwardly projecting piston rod 50. The cylinder is rigidly secured within the bracket 43 so that the piston rod f5@ `is coaxial with the bushing 44 and the upper end of the rod 42 positioned therein. The unit 4S may be hydraulically or air controlled, and is of the single acting type, with the piston normally held upwardly by a compression spring associated therewith. Supply and exhaust of actuating iluid to the upper end of the cylinder 49 is controlled by a solenoid-actuated vel-ve 51 which is supported on the pressure stripper head frame 13 and which is connected thereto by a line 52.

When the piston rod 50y is moved downwardly, by `opening of the valve 51 to supply fluid to the upper end thereof, it `enters the upper end of the bushing 44 and `as Iit does so it engages the upper end 0f the rod 42. The engaging ends of these members are dat so as to produce :a iirm contact. When the valve 51 is actuated to remove pressure from the upper end of the piston 50a, the spring in the cylinder A49 will return the piston 50a and the connected rod 50 to its uppermost position out of contact with the rod 42. At this time, the stop 45 will contact the lower end of the bushing 44, since the rod 42 is lifted to this position by the spring 46. Thus, the rods 41-42 and the associated units 48 cooperate to provide a normally yieldable connection between the pressure stripper head `frame 13 and the pallet support fname 12 which can be rendered non-yieldable by supplying iiuid pressure to the units 48.

It will be realized that at the stage when the positive rigid connection is to be made between the rods 41-42 that the vertical extent of the spaces between them will vary with variation of thickness of the successive pallets. The units 48 and the mounting thereof inherently provide variable lengths of axially disposed connectors to compensate for any variations in the vertical extent of such spaces and ll them notwithstanding such variations. When the valves 51 are actuated, the piston rods 50 will engage the rods 42 and move them downwardly to take up any space between the adjacent ends of the rods 41 and 42 which is variable in accordance with pallet thickness.

As previously indicated, the measurement which controls the height of the block being formed is taken, according to this invention, from the mold box 14 so that the thickness of the pallet 16 will have no effect on thel height of the block. By taking the height measurement' from the mold box 14, the upper surface of the pallet 16 is used as a basic reference point whereby block height measurement during iinish compaction thereof cancels out any pallet thickness variations between the pallet support frame 12 and the pressure stripper head frame 13, thereby producing block of uniform height therebetween. Therefore, as indicated, the mold box 14 is provided at each side thereof with a contact block or disc 6i) which is supported in fixed position on the mold box. For cooperating with each of the contact discs 60, a movable spring-loaded contact point 61 is associated therewith (FIGURE being mounted in axial alignment in a rod 62. Each rod 62 is mounted for vertical sliding movement in a sleeve 63 carried by the frame 13. The upper end of the rod 62 is threaded and is provided with lock nuts 64, the lower of which will engage the upper end of the sleeve 63 normally to` suspend the rod in the sleeve. Obviously, adjustment of these nuts 64 on each rod 62 will vary the vertical position of the contact point 61 relative to the frame 13. The point 61 is mounted for sliding vertical movement in a socket in the lower end of the rod 62, and downward or outward movement is limited by a transverse pin 53 carried by the rod 62 and cooperating with a Vertical slot 54 in the pin. A spring 55 tends to force the contact 61 outwardly or downwardly. As will later appear, these contacts 66 and 61, when engaged, will complete a circuit to the electromagnetic valves 51 and to the drive motor 46 and interrupt the circuit to the vibrator motors 20. The yieldably mounted point 61 will make proper contact regardless of the vibration of the contact disc 69.

In actual practice, the drive motor 46 will be a continuously operating motor and a magnetic clutch (not shown) will be provided between its drive shaft and the driven cam shaft 28. However, for simplicity, the circuit is shown as directly controlling the motor.

The circuit is illustrated in FIGURE 6 and is shown as comprising the main lines 65 and 66 leading from a suitable source of power. The line 65 is connected to a movable switch arm 67 and the line 66 to a movable switch arm 68. The arms 67 and 68 are normally spaced from the fixed contacts 69 and 76, respectively, which are connected by the respective lines 71 and 72 to the drive motor 40. The vibrating motors 29 are connected in the circuit parallel to the motor 4t? by means including the lines 73 and 74 connected to the respective fixed Contact points 75 and 76. Normally contacting with these points 75 and 76 are the respective movable switch arms 77 and 78. These arms 77 and 7S are connected to the power lines 65 and 66 by the respective lines 79 and Sti. Another circuit parallel with the motor circuits is connected to the lines 65 and 66 and includes the lines 81 and S2. Connected in series in this circuit are the two sets of contacts 60 and 61, a relay S3 and the two solenoid-actuated valves 51. The relay S3 controls the contact arms 77 and 78 which are normally engaged with the points 75 and 76. Associated with these arms 77 and 78 are the respective fixed contact points S5 and S4 that control a time delay relay S6 which, in turn, controls the contact arms 67 and 68. When the relay 83 is energized, it stops the vibrators 20 and starts timing of the relay 86, which after a set period, will energize the motor 411. The time delay relay 86 wil be actuated only when both sets of associated contacts 6i) and 61 are engaged. When both of these sets are engaged, the solenoid-actuated valve 51 will also be actuated to control the units 4S to project the piston rods 50 into engagement with the rods 42. A normally closed switch 87 is connected in the line '71 and is controlled by the cam 30 to open and break the circuit to the motor 40 after it has been energized for a predetermined period.

The nuts 64 on the contact rods 62 are adjusted to position the Contact points 61 so that they will be at a predetermined level relative to the contact discs 66 at the beginning of the molding operation. The bushing 44 6 may be screwed into and out of the bracket 43 to determine the uppermost position of the rod 42 when the stop 45 contacts with the lower end of the bushing. At this time, with the piston rod 50 retracted, the lower end of the rod 50 will `not contact with the upper end of the rod 42.

Assuming the parts of the machine are in the relative positions indicated in FIGURE l as the molding operation is nearing completion with the circuit in the condition illustrated in FIGURE 6 so that the vibrating motors 20 are operating an-d the drive motor d@ is deenergized, the sequence of operation of the machine will be as follows:

The mold box 14, having been lifted slightly from the arms 11 by the pallet 16 to permit vibration, is at this time vibrating and as the vibration continues, the contact points 61 will gradually move downwardly toward the contacts 60. As soon as contact is made, the relay 83 will be actuated and the vibrating motors 21% will be deenergized and the drive motor control timing relay 86 will -be energized. Shortly thereafter the motor 40 Will be energized thereby rotating the cam shaft 2S. The valves 51 are actuated at the same time as the relay 83 is actuated and, consequently, the piston rods 5t? will be projected downwardly into engagement with the rods 42 pushing them axially downwardly where they cause the ends of the cooperating push rods 42 and 41 to contact rmly with each other so that the pressure stripper head frame 13 will push the pallet support Ltrame 12 downwardly with it.

Stopping of the vibrating motors 2t) determines the height of the blocks being molded at that time. Rotating the cam shaft 28 will rotate the cams carried thereby and this Will produce the required relative movements of the parts of the machine. The stripper head 13 will be moved downwardly and at the same time will force the pallet 16 downwardly at the same speed. The time delay in starting the drive motor 40 after stopping the vibration insures that the units 43 will be actuated before downward movement of the stripper head 18 starts. When the pallet 16 reaches its lower position, the arms 21 will remove the iilled pallet and replace it with an empty pallet, Continued rotation of the shaft 28 will raise the pallet support frame 12, raise the stripper head 18, project the feed box 25 forwardly, Withdraw the feed box 25, deenergize the drive motor 40 and allow the stripper head to settle on the material in the feed box so that the machine will again be in the condition shown in FIGURE 1.

It will be understood that instead of the pallet support and pressure stripper head frames moving unitarily together relative to the mold box, in the stripping operation, the mold box could move relative to the couple-:l or connected frames.

It will be apparent from the above, that this invention provides a control system for a machine of the type indicated wherein the height of the block is controlled accurately without being affected by the thickness of the pallets which will vary due to the wear of the pallets. According to this invention, the height limitation is taken oli the mold box and still means is provided for insuring iirm connection between the pressure stripper head frame and the pallet support frame. This latter means embodies sets of push rods carried by the two frames, one set being rigidly carried by the one frame and the other set being connected to the other frame for relative vertical movement but having the Huid-actuated units associated therewith for locking it at times to the other frame. The cylinder and piston units comprise simple, readily available standard units for taking up the space between the adjacent ends of the cooperating push rods which space will vary in accordance with variations in pallet thickness. However, the cylinder and piston units will cooperate With the rods to couple the two frames together regardless of the variation in said space between the push rods.

According to the provisions of the patent statutes, the principles of this invention have been explained and have been illustrated and described in what is now considered to represent the best embodiment. However, it is to be understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specically illustrated and described.

Having thus described this invention, what is claimed 1. A block forming machine having a mold open at its top and bottom and means to vibrate the mold until block-forming material supplied thereto reaches a predetermined level, a pallet below the mold on which the block formed from the material rests, a pallet support frame to position the pallet to close the bottom of the mold, and a pressure stripper head frame having a pressure stripper head movable downwardly and relatively to the pallet support frame to compact said material to the said level, block height sensing means on said pressure stripper head frame and said mold movable relative to each other during the compacting operation to measure the block height from the top of the pallet, first push rod means on said support frame, second push rod means on the pressure stripper head frame vertically disposed and projecting toward each other, one of said rod means being mounted on its associated frame for sliding movement relatively to the other rod means, and coupling means on the machine normally permitting said relative sliding movement of the said rod means and capable of coupling said rod means to prevent said relative sliding movement, said coupling means comprising a Huid-actuated cylinder and piston unit mounted on said frame coaxial with said sliding rod means, said cylinder and piston unit including a piston rod projecting therefrom toward an axially aligned end of said slidable rod means, control means mounted on the machine including said height sensing means, timed to actuate, upon said level being reached, the cylinder and piston unit to couple said push rod means and accordingly said pressure stripper head and pallet support frames against relative vertical movement and to unitarily move such coupled pressure head and pallet frame vertically relative to the mold, whereby the height of the formed block is not affected by the thickness of the pallet, said control means including a control valve for actuating said cylinder and piston unit, said slidable rod means comprising a rod slidably mounted in a bracket on said pressure stripper head frame, a bushing adjustably mounted in the bracket for slidably receiving the upper end of the rod, means for slidably retaining the rod in the bushing, said cylinder and piston unit being carried by the bracket with its piston rod projecting downwardly in coaxial alignment with the upper end of the rod, and a stop on the rod for engaging the lower end of said bushing.

2. A block forming machine having a mold open at its top and bottom and means to vibrate the mold until block-forming material supplied thereto reaches a predetermined level, a pallet below the mold on which the block formed from the material rests, a pallet support frame to position the pallet to close the bottom of the mold, and a pressure stripper head frame having a pressure stripper head movable downwardly and relatively to the pallet support frame to compact said material to the said level, block height sensing means on said pressure stripper head frame and said mold movable relative to each other during the compacting operation to measure the block height from the top of the pallet, rst push rod means on said support frame, second push rod means on the pressure stripper head frame vertically disposed and projecting toward each other, one of said rod means being mounted on its associated frame for sliding movement relatively to the other rod means, and coupling means on the machine normally permitting said relative sliding movement of the said rod means and capable of coupling said rod means to prevent said relative sliding movement, said coupling means comprising a iiuid-actuated cylinder and piston unit mounted on said frame coaxial with said sliding rod means, said cylinder and piston unit including a piston rod projecting therefrom toward an axially aligned end of said slidable rod means, control means mounted on the machine including said height sensing means timed to actuate, upon said level being reached, the cylinder and piston unit to couple said push rod means and accordingly said pressure stripper head and pallet support frames against relative vertical movement and to unitarily move such coupled pressure head and pallet frame vertically relative to the mold, whereby the height of the formed block is not affected by the thickness of the pallet, said control means including a lcontrol valve for actuating said cylinder and piston unit, said slidable rod means comprising a rod slidably mounted in a bracket on said pressure stripper head frame, a bushing threaded upwardly into the, bracket for slidably receiving the upper end of the rod, said cylinder and piston unit being carried by the bracket with its piston rod projecting downwardly in coaxial alignment with the upper end of the rod, a stop on the rod for engaging the lower end of said bushing, and a spring connected to said bracket and to said rod and normally pulling it upwardly to cause said stop to engage the lower end or said bushing.

References Cited in the tile of this patent UNITED STATES PATENTS 2,331,015 Dawes et al. Oct. 5, 1943 2,926,412 Stacy et al Mar. 1, 1960 2,985,935 Wellnitz May 30, 1961 

1. A BLOCK FORMING MACHINE HAVING A MOLD OPEN AT ITS TOP AND BOTTOM AND MEANS TO VIBRATE THE MOLD UNTIL BLOCK-FORMING MATERIAL SUPPLIED THERETO REACHES A PREDETERMINED LEVEL, A PALLET BELOW THE MOLD ON WHICH THE BLOCK FORMED FROM THE MATERIAL RESTS, A PALLET SUPPORT FRAME TO POSITION THE PALLET TO CLOSE THE BOTTOM OF THE MOLD, AND A PRESSURE STRIPPER HEAD FRAME HAVING A PRESSURE STRIPPER HEAD MOVABLE DOWNWARDLY AND RELATIVELY TO THE PALLET SUPPORT FRAME TO COMPACT SAID MATERIAL TO THE SAID LEVEL, BLOCK HEIGHT SENSING MEANS ON SAID PRESSURE STRIPPER HEAD FRAME AND SAID MOLD MOVABLE RELATIVE TO EACH OTHER DURING THE COMPACTING OPERATION TO MEASURE THE BLOCK HEIGHT FROM THE TOP OF THE PALLET, FIRST PUSH ROD MEANS ON SAID SUPPORT FRAME, SECOND PUSH ROD MEANS ON THE PRESSURE STRIPPER HEAD FRAME VERTICALLY DISPOSED AND PROJECTING TOWARD EACH OTHER, ONE OF SAID ROD MEANS BEING MOUNTED ON ITS ASSOCIATED FRAME FOR SLIDING MOVEMENT RELATIVELY TO THE OTHER ROD MEANS, AND COUPLING MEANS ON THE MACHINE NORMALLY PERMITTING SAID RELATIVE SLIDING MOVEMENT OF THE SAID ROD MEANS AND CAPABLE OF COUPLING SAID ROD MEANS TO PREVENT SAID RELATIVE SLIDING MOVEMENT, SAID COUPLING MEANS COMPRISING A FLUID-ACTUATED CYLINDER AND PISTON UNIT MOUNTED ON SAID FRAME COAXIAL WITH SAID SLIDING ROD MEANS, SAID CYLINDER AND PISTON UNIT INCLUDING A PISTON ROD PROJECTING THEREFROM TOWARD AN AXIALLY ALIGNED END OF SAID SLIDABLE ROD MEANS, CONTROL MEANS MOUNTED ON THE MACHINE INCLUDING SAID HEIGHT SENSING MEANS, TIMED TO ACTUATE, UPON SAID LEVEL BEING REACHED, THE CYLINDER AND PISTON UNIT TO COUPLE SAID PUSH ROD MEANS AND ACCORDINGLY SAID PRESSURE STRIPPER HEAD AND PALLET SUPPORT FRAMES AGAINST RELATIVE VERTICAL MOVEMENT AND TO UNITARILY MOVE SUCH COUPLED PRESSURE HEAD AND PALLET FRAME VERTICALLY RELATIVE TO THE MOLD, WHEREBY THE HEIGHT OF THE FORMED BLOCK IS NOT AFFECTED BY THE THICKNESS OF THE PALLET, SAID CONTROL MEANS INCLUDING A CONTROL VALVE FOR ACTUATING SAID CYLINDER AND PISTON UNIT, SAID SLIDABLE ROD MEANS COMPRISING A ROD SLIDABLY MOUNTED IN A BRACKET ON SAID PRESSURE STRIPPER HEAD FRAME, A BUSHING ADJUSTABLY MOUNTED IN THE BRACKET FOR SLIDABLY RECEIVING THE UPPER END OF THE ROD, MEANS FOR SLIDABLY RETAINING THE ROD IN THE BUSHING, SAID CYLINDER AND PISTON UNIT BEING CARRIED BY THE BRACKET WITH ITS PISTON ROD PROJECTING DOWNWARDLY IN COAXIAL ALIGNMENT WITH THE UPPER END OF THE ROD, AND A STOP ON THE ROD FOR ENGAGING THE LOWER END OF SAID BUSHING. 